It is usually the case that such electrical machines, for example permanently excited synchronous machines, but also externally excited machines, reluctance machines or hybrid machines, use an entire sheet assembly containing a plurality of electrical sheets.
The electrical sheets have narrow crosspieces, in particular on the periphery of pockets, that is to say of recesses such as magnet pockets for accommodating permanent magnets. In order to reduce the magnetic conductivity of the electrical sheets in the region of the magnet pockets, and for the resulting increase in the magnetic flux which helps to provide the torque of the electrical machine, it is known for magnet pockets to be configured such that crosspieces which are as thin as possible form in the vicinity of the magnet pockets.
An embedded magnet motor with a rotor, the rotor comprising a rotor core, wherein the rotor core comprises radial accommodating slots, first oblique accommodating slots and second oblique accommodating slots, is known, for example, from DE 102008044127 A1. Portions of each radial accommodating slot on which the longitudinal slots are provided form interspaces in respect of the associated radial magnet. The magnetoresistance is increased in this way. The longitudinal slots separate the magnetic paths from the radial magnet.
In order to produce electrical sheets, it is known for the required shapes to be punched, for example, out of a disk of sheet metal.
DD 242 057 A1 discloses a method of reducing eddy-current losses for isotropic electrical steel sheets, wherein an annealed sheet, finally, is cold formed again with a low degree of deformation.